Tamarind seed polysaccharide (TSP) is a natural polysaccharide polymer obtained from the seeds of Tamarindus indica, an evergreen plant which can reach a height of 15 meters and produces fruit in the form of pods. It is very common in India, Africa and throughout the Far East, where it is mainly grown as a food. The fruit contains large seeds with a high percentage of polysaccharides, which have the function of accumulating and preserving vital energy-giving substances. Tamarind seeds, which were originally considered as waste products, have subsequently found different applications after grinding to obtain a farinaceous product (known as tamarind gum or tamarind nut powder). The most important of these applications is in the textile industry and the paper industry, where tamarind gum is used as a sizing and gluing agent, and in the food industry where, like other polysaccharides, it is used as a thickener, gelling agent, stabiliser and binder in various products. Raw tamarind gum is a commercially available product containing from 65% to 73% by weight of polysaccharide, from 15% to 23% by weight of protein material, from 3% to 8% by weight of fats and oils, and from 2% to 4% by weight of ash, together with smaller amounts of raw fibre, tannins and other impurities.
More recently, TSP has also been used in the pharmaceutical field as active ingredient in tears substitutes (WO2009/044423), as a carrier for slow-release ophthalmic medicaments for topical administration (WO97/28787) and, more generally, as an excipient due to its mucoadhesive characteristics (WO2006/131262).